In applications where the development of a high degree of durability and toughness under ambient conditions-are important, polymers dispersed in organic solvent have traditionally been employed or used. Additionally, solvent based polymers allow the formulator to produce coatings with all the necessary formulation ingredients in a single package. However, more recently, solvent based coatings have come under extreme pressure because of health, safety and environmental concerns. In an attempt to address these concerns, formulators are demanding from raw material suppliers polymers which give equivalent performance with decreasing levels of volatile organic solvents. In response to health, safety and environmental concerns, formulators have increased their use of aqueous based polymers.
However, aqueous based polymers, when cured under ambient conditions, have inherent shortcomings with respect to durability and to toughness when compared to solvent based polymers. Consequently, waterborne coatings have not found wide acceptance in applications where strength and durability are important. Another shortcoming of aqueous based polymers is the need for multiple package systems for equivalent performance of solvent based systems. Multiple package systems require the end-user to mix at least two components prior to the coating application. However, there are instances where the use of multiple package systems are impractical and inconvenient.
What we have found to be novel and unanticipated is a waterborne or water dispersed polymer which cures at ambient temperature and can be formulated into a single package coating, and has the durability and toughness of solvent based polymer systems. This is accomplished by post-reacting an acetoacetoxy functional polymer with an amine-functional silane.